Automatic screw driver



Sept. 1; 1931; G, R, wlLcox 1,821,194

AUTOMATIC SCREW DRIVER Filed Dec. 1, 1930 19 1.9 s INVENTOR j ATTORNEY Patented Sept. 1, 1931 UNITED STATES PATENT OFFICE GEORGE R. WILCOX, OF GREENFIELI), MASSACHUSETTS, ASSIGNOR T0 MILLERS FALLS COMPANY, OF MILLERS FALLS, MASSACHUSETTS, A CORPORATION OF MASSACHU- SETTS AUTOMATIC SCREW DRIVER Application filed December 1, 1930. Serial No. 499,165.

This invention relates to spiral ratchet screw drivers and more particularly to the mechanism for controlling the direction in which the tool, operated by the screw driver is rotated.

Screw drivers of this general type, as constructed heretofore, are provided with a tool carrying spindle which is slidably and rotatably mounted in a hollow handle or holder. This spindle is commonly provided with spiral grooves extending in opposite directions throughout the greater portion of the spindle, and spiral ratchet nuts are rotatably mounted in the hollow handle or holder to receive and rotate the spindle in opposite directions, the operation of each ratchet nut being controlled by a dog.

These dogs have been variously constructed, heretofore, and in many screw drivers are supported so that they may be rocked in a plane extending longitudinally of the screw driver into and out of locking engagement with the adjacent spiral ratchet nut, but the dogs when so constructed are subjected to a lateral or bending thrust as they hold a ratchet nut from rotating. Furthermore various forms of sliding and rotating devices have been provided heretofore for manual operation to disengage either dog from its ratchet to thereby control the direction in which the tool operated by the screw driver is rotated.

The present invention seeks to improve the ratchet holding dogs of the prior constructions and the manually operable means for disengaging either dog from its ratchet nut, and relates to an extremely simple and reliable construction to this end.

One important feature of the present invention resides in a ratchet holding dog that is mounted transversely of the screw driver to swing in a transverse plane, and in the construction for supporting the dog for rocking movement to and from the ratchet holding position.

A more specific feature of the invention resides in a laterally extending dog having dog supporting and tilting projection and means mounted on the rotating or enclosing shell and adapted to engage this projection to hold a dog out of engagement with its ratchet.

Another feature of the invention resides in prong-like projections on each dog adapted to straddle the ratchet portion of a spiral nut and to help hold the dog in place, and

in improvements in the spiral mechanism for causing the ratchet nuts to rotate the spirally grooved spindle.

Other featuresof the invention and novel arrangement of parts, in addition to the above, will be hereinafter described in connection with the accompanying drawings which illustrate one good practical form of the invention.

Inthe drawings:

Fig. l is a side elevation of a ratchet screw driver, constructed in accordance with the present invention. 7

Fig. 2 on an enlarged scale, is a view similar to Fig. 1 showing the outer shell and the nut for holding the same in place, shifted lengthwise of the spiral spindle.

Fig. 3 is a longitudinal sectional view through the body portion of the screw driver in which the ratchet nuts are rotatably mounted.

Fig.4 is a plan view of the right and left hand dogs and the spring for holding these dogs in engagement with the ratchet nuts.

Fig. 5, on an enlarged scale, is a sectional view taken on the line 5-5 of Fig. 1.

Fig. 6 is a similar view taken on the line 6-6 of Fig. 1, and

Fig. 7 is a sectional view taken on the line 77 of Fig. 2.

The spiral ratchet screw driver as shown in Fig. 1 of the drawing has the usual tubular holder 10, which is provided at its outer end with the handle 11, formed of wood or other material which will afford a good grip to the hand of the person using the screw driver. The tubular holder 10 is provided at its opposite end with an enlarged body portion 12, in which the spiral ratchet nuts 13 and 14 are rotatably mounted. Each of these nuts is shown as having a central ratchet portion, and a hub portion adjacent each end and of reduced diameter, as clearly shown in Fig. 3. The ratchet portion of one of these nuts faces in a right hand direction while the ratchet portion of the other nut faces in a left hand direction, and the nut 13, in the construction shown, is held against movement lengthwise in one direction by the shoulder 15, formed in the bore of the body portion 12 at one end thereof, and the nut 13 is held against movement in the opposite direction by a key, or the like 16, which is snugly mounted in a sawslot formed in a wall of the body portion 12 and extends inwardly, far enough to engage an end of the nut 13.

Within the tubular holder 10, is slidably and rotatably mounted the tool operating spindle 17, which is provided throughout the greater portion of its length with the oppositely extending spiral grooves 18 and 19, and in the construction shown the grooves 18, employed to rotate the spindle and tool carried thereby, in a right hand direction, are made deeper than the grooves 19 provided to rotate the spindle in the opposite direction. The spindle illustrated, as will be apparent from Fig. 7, is provided with two deep grooves 18, and two more shallow grooves 19, and the ratchet nut 13 is shown as having two relatively deep spiral keys 20, adapted to cooperate with the deep grooves 18, of the spindle, to rotate the same in the right hand direction, while the ratchet nut 14 is shown as having the two spiral keys 21, of less depth, and adapted to engage the grooves 19 to rotate the spindle in the left hand direction.

The spindle 17 is shown in Fig. 1 as provided at its lower end with the usual screw driver blade 22, the shank portion of which is removably secured in the holder 23, at thelower end of the spindle 17. This holder may be of well known construction and is shown as having the sleeve 24, which is rotatably and slidably mounted upon the holder 23, and is normally held by a spring, (not shown) in its depressed position so as to maintain a locking ball, (not shown) in engagement with an annualr groove 25, provided in the shank of the screw driver blade, and the blade is provided at its upper end with the key portion 26, adapted to enter a correspondingly shaped slot in the spindle 17.

The spiral ratchet nut 13, in accordance with the present invention is provided with a cooperating dog 27, adapted to hold this ratchet from rotating in a clockwise direction, as will be apparent from Fig. 5, while the ratchet nut 14 is provided with a similarly constructed dog 28, adapted to hold its nut from rotating in a contraclockwise direction, as will be apparent from Fig. 6. Each of the dogs 27 and 28 is provided at one end with a dog supporting and tilting projection 29, and each of these dogs is preferably provided at its opposite end with a pair of spaced prongs 30, positioned to straddle the ratchet portion of the nut with which it cooperates.

These dogs are mounted in clearance recesses, formed in the body portion 12 of the tubular holder, and in the construction shown the dog receiving recesses are formed by providing the body portion 12 with a relatively wide slot 31, that is formed entirely through one wall of the body portion and extends throughout the greaterportion of the length of the body portion as shown in Fig. 2. The body portion 12 is also provided with the transversely extending slots 32, formed about midway between the ends of the body portion, as will be apparent from Fig. 2, and these slots 32 are adapted to snugly receive the ends of the dog-holding spring 33. This spring is preferably made of very thin tempered steel and need not be more than l/lOOths of an inch in thickness, so that it will bow transversely slightly when forced into the slot 32 to fit tightly therein, and the spring 33 is provided with the oppositely extending resilient fingers 34 that are bent laterally somewhat to the plane of the spring as shown in Fig. 6 to en gage the dogs. The portion 12 of the screw driver is also provided with the transversely extending slots, or recesses 35, disposed over the ratchet portion of the nuts 13 and 14. The slots 35 form clearance spaces to receive the projections 29, of the dogs 27 and 28. The arrangement is such that each dog is supported for rocking movement in a plane transversely of the screw driver, by its projection 29, that is seated in a slot 35, and each dog is further retained in position by the spaced prongs 30, adapted to straddle the ratchet portion of the spiral nut with which the dog is associated and the ends of these prongs may abut against the adjacent wall 31, as will be apparent from Figs. 5 and 6 to limit the movement of the dog transversely of the screw driver.

It will be seen from the foregoing that each of the dogs 27 and 28 is extremely simple in construction, and that since a ratchet engaging edge 36 of a dog engages a tooth of a ratchet nut, as shown in full lines in Figs. 5 and 6, any tendency of the ratchet nut to rotate exerts a positive thrust upon the dog in the direction of its length and is resisted by the abutting engagement of the shoulders 37, of the dog against a wall 31. As a result of this construction a dog formed of relatively thin sheet metal is capable of resisting a powerful thrust, exerted upon the same by its spiral nut.

As above stated the resilient fingers 34 normally hold the dogs 27 and 28 in looking engagement with the spiral nuts 13 and 14, as shown in Fig. 2, and when both dogs engage the locking nuts the spindle 17 will be held against rotation in either direction.

When it is desired to rotate the spindle 17 in a right hand direction by reciprocating the tubular holder 10, and handle 11, upon the spindle, the dog 28 is moved out of engagement with its nut 14, as shown in dotted lines in Fig. 6; and when it is desired to operate the screw driver to rotate the spindle in the left hand direction the dog 27 is shifted to the dotted line position of Fig. 5.

The shifting of the dogs 27 and 28 to their inoperative position is accomplished in accordance with the present invention by forming the projection 29 of each dog so that it is bent or offset laterally from the plane of the dog, as clearly shown in Figs. 5 and 6, the arrangement being such that when either dog is in its nut locking position the projection 29 extends upwardly somewhat in a position to be engaged and tilted by one of the lugs 38 and 39, riveted or otherwise secured to the inner face of the shell 40 which is rotatably mounted upon the body portion 12 to house and protect the pawl and ratchet mechanism enclosed therein. The body portion 12, is provided with a clearance slot 41 at its outer end, adapted to clear the lugs 38 and 39, as the shell 40 is slipped over the body portion, and into the position in which it is shown in Fig. 1. Rotation of the shell 40 in one direction will engage its lug 38 with the dog 27 to move the same to its inoperativeposition and rotation of the shell in the opposite direction will engage its lug 39 with the dog 28 to render this dog inoperative. The spring 33 is conveniently secured in its operating position by simply forming its ends so that they will fit snugly in the slots 32.

The shell, or protecting sleeve 40, is held against movement lengthwise of the body portion 12 in one direction by the shoulder 42 and is held against movement in the opposite direction by the ring nut 43, which is provided with the threads 44, adapted to engage the internal threads 45 formed in the body portion 12. This nut 43 serves also to hold the spiral ratchet nut 14 against movement in one direction within the body portion 12, while this spiral nut is held against movement in the opposite direction by the key 16.

The ring nut 43 is preferably provided with the knurled ring 46 rotatably mounted upon the nut 43, and adapted to operate a locking ball, (not shown), which is supported within the nut 43 in position to engage the annular groove 47 formed in the shank 17 to lock this spindle against movement lengthwise of the tubular holder 10, upon rotation of the nut 46 in the proper direction.

It will be seen from the foregoing that the dogs 27 and 28 are extremely simple in construction and that this is also true of the means for operatively supporting the dogs in the body portion 12, and as a result'of the present invention, whereby the turning action of each ratchet nut exerts a thrust upon the dog in the direction of its length, the turning force is resisted without subjecting the dog to a twisting or other distorting stresses. It will also be seen from the foregoing that by forming the spiral grooves 18 deeper than the grooves 19 a more durable and smoother operating screw driver is produced.

\Vhat is claimed is 1. In a spiral ratchet screw driver, in combination, a tubular holder provided with a body portion having dog positioning slots, a toolcarrying spindle slidable in the holder and provided with oppositely extending spiral grooves, a spiral ratchet nut for each groove rotatably mounted in said body portion, a dog for each ratchet nut, a projection upon each dog extending into a positioning slot to support the dog for rocking move ment in a plane extending transversely of the screw driver, a pair of prongs upon each dog and positioned to straddle the ratchet portion of its spiral nut and adapted to help hold the dog in place, and manually operable means for holding either dog out of en.- gagement" with its ratchet nut.

2. In a spiral ratchet screw driver, in com-- bination, a tubular holdenprovided with a body portion having a spring retaining slot, a tool carrying spindle slidable in the holder and provided with oppositely extending spiral grooves, a spiral ratchet nut for each groove rotatably mounted in said body portion, a dog for each ratchet, means for supporting each dog for rocking movement in a plane extending at right angles to the screw driver, a shell rotatably mounted upon said body portion, afiat spring extending transversely of said body portion and having its ends forcedinto said slot to thereby maintainthe spring in operative position out of contact with said shell, resilient fingers extending laterally from said spring and operable to engage the dogs with their ratchet nuts, and means upon said shell for holding either dog out of engagement with its ratchet nut.

3. In a spiral ratchet screw driver, in combination, a tubular holder provided with a body' portion, a tool carrying spindle slidable in the holder and provided with oppositely extending spiral grooves, a spiral ratchetnut for each groove rotatably mounted in said body portion, a dog for each ratchet nut extending transversely of the screw driver and provided at one end with a supporting and tilting projection adapted to support the dog for rocking movement in a plane extending transversely of the screw driver and provided at its opposite end with spaced prongs positioned to straddle the ratchet portion of a spiral nut, and a shell rotatable uponsaid body portion and pro; vided with means for engaging said projections to disengage either dog from its ratchet nut.

4. In a spiral ratchet screw driver, in combination, a tubular holder provided with a body portion, a tool carrying spindle slidable in the holder and provided with oppositely extending spiral grooves, one of which is deeper than the other, spiral ratchet nuts rotatably mounted in said body portion to receive said shank, one nut being provided with a deep spiral key to enter said deep groove and the other with a more shallow spiral key to enter the said shallow groove, and dogs cooperating with said spiral grooved nuts.

5. In a spiral ratchet screw driver, in combination, a tubular holder provided with a body portion having a slot extending longitudinally thereof, and provided with notched portions extending laterally from the slot, a tool carrying spindle slidable in the hold er and provided with oppositely extending spiral grooves, a spiral ratchet nut for each 'groove rotatably mounted in said body portion, a dog for each ratchet nut extending transversely of the spindle and each provided with a projection extending into one of said notched portions to rockingly support the dog, a pair of prongs upon each dog adapted to straddle the ratchet portion of its spiral nut and to engage a wall of said slot to hold the dog from moving transverse-.

ly of said slot, spring means for engaging each dog with its ratchet nut, and manually operable means for holding either dog out of engagement with its ratchet nut.

6. In a spiral ratchet screw driver, in combination, a tubular holder provided with a body portion having a dog positioning slot, a tool carrying spindle slidable in the holder and provided with a spiral groove, a spiral ratchet nut for said groove rotatably mounted in said body portion, a projection on said dog extending into said positioning slot to support the dog for rocking movement in a plane extending transversely of the screw driver, a pair of prongs upon said dog positioned to straddle the ratchet portion of the spiral nut to help hold the dog in place, a spring for engaging the dog with its ratchet, and manually operable means for moving the dog out of engagement with the ratchet nut.

In testimony whereof, I have signed my name to this specification.

GEORGE R. VVILCOX; 

